Understanding BRCA1/2 Gene Mutations
Everyone — male and female — has BRCA1 and BRCA2 genes (often written as BRCA1/2). BRCA1/2 are a type of gene called tumor suppressor genes, which means that they play a role in preventing cancers from developing in our bodies. Some people have an inherited mutation in their BRCA1 or BRCA2 genes that puts them at increased risk of certain cancers, including breast, ovarian, prostate, and melanoma. These mutations can be passed down to children, meaning that children who inherit a BRCA mutation from a parent will have increased BRCA-related cancer risks in adulthood.1
Having a BRCA1 or BRCA2 mutation does not mean that you will definitely develop one or more BRCA-related cancers. However, people with BRCA1/2 mutations that develop cancer tend to develop BRCA-related cancers at younger ages and, in some cases, these cancers may be more aggressive.
Sporadic vs. hereditary cancers
Most cancers are considered sporadic, meaning that they develop due to a combination of factors including environmental exposures, hormones, and normal cell damage that accumulates over a person’s lifetime. Hereditary cancers are those that are due, in part, to inheriting a mutation from a parent that increases the risk of developing certain cancers. About 5-10% of breast cancers and 10-15% of ovarian cancers are considered to be hereditary.1,2
What cancers are associated with mutations in BRCA1 and BRCA2?
Mutations in BRCA1/2 are most commonly associated with an increased risk of breast, ovarian, pancreatic, and prostate cancer, as well as melanoma. The heightened risk will depend if the mutation is in BRCA1 or BRCA2.2 BRCA1 carriers are at an increased risk of developing triple-negative breast cancer. BRCA1/2 carriers are also at an increased risk of developing a second primary breast cancer.1
How common are BRCA gene mutations?
In the general population, about 1 in 400 to 1 in 500 people will carry a BRCA mutation. However, some groups of people may be at increased risk of carrying a BRCA mutation. Individuals of Askenazi Jewish descent (Eastern and Central European descent) have a nearly ten times greater risk of carrying a BRCA gene mutation. 1 in 40 people of Ashkenazi Jewish descent will have a BRCA mutation.2
How do I find out if I have a BRCA gene mutation?
Genetic testing can be done to determine if an individual has a mutation in BRCA1 or BRCA2. Typically, an individual will see a genetic counselor to review their personal and family history of cancer, which allows the counselor to determine if genetic testing is warranted. To find a genetic counselor in your area, the National Society of Genetic Counselors directory can be a helpful place to start.
Does knowing about a BRCA mutation change the treatment for BRCA-related cancer?
Knowing about a BRCA mutation can impact the treatment of individuals with BRCA-related cancer. There are also clinical trials that may be available to people with BRCA-related cancer. Some types of treatments have been shown to be more effective in individuals with certain BRCA-related cancers. For example, several PARP inhibitors have been approved for the treatment of metastatic breast cancer in people with a BRCA mutation.2,3Additionally, in addition to treating their cancer, people with a known BRCA mutation can simultaneously undergo additional risk management and consider risk reduction strategies for other BRCA-related cancers.
How do I manage BRCA-related cancer risks if I don’t have a particular type of BRCA-related cancer?
It is important to share the results of your genetic testing with your health care team so that you can develop an appropriate risk management plan. Risk management plans can include increased cancer screenings that may begin at a younger age, such as breast MRIs and mammograms, or consideration of risk-reducing surgeries, such as a prophylactic mastectomy or bilateral salpingo-oophorectomy (removal of the ovaries and fallopian tubes).4 By working together with your healthcare team, you can determine a risk management plan that best meets your needs and preferences.
Other hereditary gene mutations that impact cancer risk
Although BRCA1/2 are well-understood gene mutations that impact cancer risk, they are not the only ones. There are other known hereditary mutations that can have an impact on cancer risk. A genetics specialist can help to determine what genes should be tested based on your personal and family history of cancer.
Have you gotten a second (or third) opinion after your breast cancer diagnosis?